* Rework language service and API
* Revert unintended commit of Directory.Build.props
* Create OS conditional test for invalid ISO codes
* Reintroduce and obsolete old Delete method on ILocalizationService + make new Delete method delete by ISO code + add obsoletion attrs to service implementation
* Review comments + utilize new Delete method
* Do not allow model reuse when creating a new language
* Fix bad merge
* Split localization service into dedicated services for language and dictionary item handling
* Replaced ILocalizationService usage in management API (as much as can be done for now)
* Ensure we can create dictionary items with explicit keys (but no duplicates)
* Fix culture controller so it works properly with pagination
* Update OpenAPI JSON
* Actually update the language being updated...
* Unit test for invalid ISO now no longer needs to differ between OS :)
* A little bit of code health improvements
* A litte less code duplication
* Remove duplicate validation
* Rework dictionary CRUD operations
* Update OpenAPI json
* Move responsibility to localization service, introduce new attempt pattern for create and update operations, update unit tests accordingly
* Fix merge
* Rollback assumption that we can map entities from scratch (entity relations got in the way)
* Update OpenAPI JSON
* Add breakage supressions
* Add compat suppressions for integration test project
* Make dictionary item deletion follow same pattern as create and update
* Review comments + update delete to use new pattern
* Update breakage suppressions to match the new Delete method
* Created a common library for the APIs and moved stuff that is required for the new content API. Also moved the versioned backoffice API route handling to the management API where it belongs.
* Remove test auth attribute from Media
